package Text;

public class Circle {
    public static final double PI = Math.PI;

    private double radius;

    public Circle(double radius)
    {this.radius = radius;}
    public double area()
    {return PI * Math.pow(radius, 2);}

    public static void main(String[] args) {
        Circle circle = new Circle(10);
        System.out.println("圆的面积: " + circle.area());
    }
}


